Li uzas penikon por meti farbon sur la muron.

The ending -n usually marks the accusative in Esperanto.

In this sentence:

• penikon = the direct object of uzas (uses what? a brush)
• farbon = the direct object of meti (put what? paint)
• muron is a little different: after a preposition, -n can show motion toward something, not just a direct object

So not every -n here does exactly the same job, but they are all examples of the accusative ending being used.

Because Esperanto often distinguishes:

• location: sur la muro = on the wall
• movement toward that location: sur la muron = onto the wall

Here the paint is being put onto the wall, so sur la muron makes sense.

A useful contrast:

• La farbo estas sur la muro. = The paint is on the wall.
• Li metas farbon sur la muron. = He puts paint onto the wall.

Por means for or in order to, and meti is an infinitive, meaning to put.

So por meti farbon sur la muron means:

• to put paint on the wall
• or more naturally, in order to put paint on the wall

This is a very common Esperanto pattern:

• Mi venis por helpi. = I came to help.
• Ŝi uzas ĝin por lerni. = She uses it to learn.

Yes, meti literally means to put or to place.

In this sentence, it is being used in a broader sense: to put/apply paint on the wall. That is perfectly understandable Esperanto.

Depending on style and context, Esperanto speakers might also use other expressions, but meti farbon sur la muron is a clear and straightforward way to say it.

-as is the present-tense verb ending in Esperanto.

So:

• uzas = uses / is using
• meti = to put
• li uzas = he uses / he is using

Esperanto’s present tense often covers both English simple present and present continuous, depending on context.

Usually, yes. Peniko is the word you would expect for a brush used to apply paint or something similar.

That is why Li uzas penikon strongly suggests He uses a paintbrush in this context.

This helps distinguish it from other kinds of brushes that may have different words in Esperanto.

Esperanto has:

• la = the
• no indefinite article for a/an

So:

• penikon can mean a brush or brush
• farbon can mean paint or some paint
• la muron means the wall

Whether something is definite or indefinite often depends on context. Esperanto does not have a separate word for a/an.

Yes, to some extent. Esperanto word order is fairly flexible because endings show grammatical roles.

The neutral order here is:

• Li uzas penikon por meti farbon sur la muron.

But some rearranging is possible, especially for emphasis, for example:

• Por meti farbon sur la muron, li uzas penikon.

That said, the original version is the most straightforward and natural for a learner to follow.

The endings help a lot.

• Li uzas penikon: penikon is the object of uzas
• por meti farbon sur la muron: inside this infinitive phrase, farbon goes with meti
• sur la muron tells you where the paint is being put

So the sentence is built like this:

• main clause: Li uzas penikon
• purpose phrase: por meti farbon sur la muron

This kind of structure is very common in Esperanto.